The overall goal of the proposed research is to employ chemoenzymatic monomer synthesis, parallel polymer synthesis and cheminformatic modeling for the design and evaluation of polymers for transgene delivery. Gene-based strategies, designed to manipulate cellular phenotype by introducing exogenous genes, are attractive in therapeutic and functional genomics applications. Currently available non-viral (e.g. polymeric) gene delivery vectors are limited by toxicities and suffer from low efficacies. We hypothesize that a synergistic combination of rational chemoenzymatic synthesis of monomers and combinatorial polymer synthesis will lead to the rapid identification polymers with high efficacies for delivering genes to cells (Specific Aim 1). The rapid generation of transfection data will facilitate the construction of predictive Quantitative Structure-Activity Relationship (QSAR) cheminformatic models that correlate gene delivery efficacy with polymer and polyplex physicochemical properties (e.g. molecular weight, hydrophobicity, zeta potential, etc.) using Support Vector Machine (SVM) and Kernel-Partial Least Squares (K-PLS) regression (Specific Aim 2). A novel QSAR 'model- of models' approach will be developed in which, polymer physicochemical properties will first be estimated using predictive QSAR models based on monomer structure. QSAR models for transgene expression will then be generated using these estimated properties as a result of which, predictions of transgene expression efficacy will be based directly on monomer structures. In the long-term, such predictive QSAR models will aid in the rational design of high-efficacy polymeric transfection agents, which a powerful approach for non-viral gene delivery. Recognizing that polymer-mediated transgene expression suffers from low efficacies, we will employ a combination treatment approach using mediators of intracellular trafficking and transcription (chemotherapeutic enhancers), designed to enhance transgene expression in cells (Specific Aim 3). Finally, effective polymers along with chemotherapeutic enhancers will be employed for delivering genes that encode TRAIL, which selectively induces apoptosis in cancer cells, both in vitro and in vivo (Specific Aim 4). SCID mouse xenograft models will be employed to investigate recession of 22Rv1 prostate tumors, and biodistribution and toxicity of the polymer-plasmid complexes will be investigated. It is anticipated that the proposed research will result in the identification of (1) new effective polymers for non-viral gene delivery, (2) insights into polymer physicochemical factors that influence transgene delivery, (3) predictive QSAR models that will facilitate high-throughput 'in silico' identification of effective polymers, and (4) in vivo efficacy and biodistribution evaluation of polymer-based delivery. It is anticipated that this research will significantly impact gene-based therapeutics, functional genomics, and various applications that depend on high levels of transgene expression in cells. The proposed research will develop novel non-viral (polymeric) materials for gene delivery and evaluate them in vitro and in vivo. These will find significant application in gene therapy for a number of diseases and will expand therapeutic options in these cases.